Article: Understanding a Marine Wilderness (in Parts)

What does the word “wilderness” bring to mind? Likely, the mental picture is of vast stretches of trees, not vast stretches of coral reefs, or underwater lawns of seagrass, or miles of open ocean. “We have official wilderness areas on land,” says marine biologist Dan Brumbaugh. “Many people think we need wilderness in the marine realm as well, where nature is allowed to be as natural as possible.”

About 50 years ago, 456 square kilometers of The Bahamas, a 700-island archipelago, was set aside to be “always preserved for study in [its] primordial state.” For decades, some fishing was allowed in this region, called the Exuma Cays Land and Sea Park, but in 1986 the reserve was designated “no-take”—nothing in its borders could be fished, pulled, or otherwise extracted.

Exuma Cays Land and Sea Park is one of the largest no-take marine reserves in the world. In total, less than 0.5 percent of the oceans are safeguarded in some fashion, falling under the umbrella term “marine protected areas.” The subset of marine protected areas that are strictly no-take reserves consists of less than .0001 percent of global waters.

This coverage is paltry given the extent of marine ecosystem degradation. Eighty percent of coral cover on Caribbean reefs has disappeared in the last three decades. Around the world, overfishing, coastal development, pollution, and climate change are exacting an increasing toll. The levels of large predatory fish have dropped 90 percent since preindustrial times. The absence of these fish has radically affected the health of the entire ocean ecosystem, whose watery surface easily conceals its maladies.

Some marine life is also having trouble sustaining itself in the face of new technology. “At one time, organisms had natural refuges—places where people couldn't get to,” explains Brumbaugh. “The refuges helped maintain those populations that were heavily fished elsewhere. But now people can access more fishing spots, mark them with a GPS unit, and find them over and over again, even without visible landmarks. Marine reserves can help create new refuges from these efforts.”

Sustaining marine resources is crucial in a place like The Bahamas, where people rely on the ocean for their livelihood and lifestyle. The Bahamian government is planning a network of no-take marine reserves that may eventually set aside 20 percent of the archipelago. The sites for the first five reserves have already been designated. But where exactly should their boundaries lie? How many reserves are necessary to both protect marine life and replenish economically critical fisheries? The answers require an understanding of how biological, geophysical, and human components play a role in the marine environment. This line of system-level thinking has its own new term: biocomplexity.

About four years ago, a team of American, British, and Bahamian ecologists, geneticists, anthropologists, economists, mathematicians, and other scientists organized to investigate marine reserves in The Bahamas. The study, called the Bahamas Biocomplexity Project, is led by the American Museum of Natural History’s Center for Biodiversity and Conservation (CBC) with primary funding by the National Science Foundation.

The scientists, who are organized into three working groups, are now measuring biological, sociological, and “connectivity” (how the system “flows” genetically and hydrographically) aspects of The Bahamas. As the five-year project enters its final stages, the data gathered are being merged into computer models that describe the Bahamas’ complex ocean system and predict how changes will affect it. Studies of the 20-year no-take performance record of the Exuma Cays Land and Sea Park provide important pieces of the puzzle. The hopes are that the data from this “experimental control” of a marine wilderness can be applied to marine reserves across The Bahamas and even worldwide.

Habitat Work

The boundaries of Exuma Cays Land and Sea Park corral a string of hundreds of tiny islands near the center of the Bahamian archipelago. In the west of the park, the sandy seafloor rises gently from mangrove-fringed island edges. The deepwater Exuma Sound plunges to the east. Around the islands, channels of fast-flowing water mingle with patchy coral reefs and “hardbottom” limestone plains dotted with seagrass beds, sponges, algae, and sea fans and other soft corals. This range of habitats supports a diversity of organisms. It’s also an extraordinarily pretty office.

Bahamas Biocomplexity Project scientists often videotape "quadrats" of seafloor to enumerate the marine life that visit them over time.

Kate Holmes, a CBC marine scientist, occasionally works here. By surveying the number and size of the organisms in these habitats and then comparing the data to those in similar habitats say 2, 10, or 70 km outside of the park, Holmes and her colleagues are quantifying how well a marine reserve protects its charges.

The habitat team is especially curious about several species key to Bahamian commercial fisheries. One is Nassau grouper, a striped predator which once was ubiquitous in Caribbean reefs. The fish has now been caught to rarity in most places, but it remains fishable, though in depleted numbers, in The Bahamas.

Previous studies of Nassau grouper in The Bahamas had shown that its density in the park was at least double that 30 km outside of the park. The park groupers themselves were also 20 percent larger. Research by the Bahamas Biocomplexity Project is now focusing on how these greater numbers of groupers in the park affect parrotfishes, an herbivorous prey of grouper that help keep corals from being overgrown by algae.

Social Work

Other researchers in the Bahamas Biocomplexity Project survey Bahamians instead of fish. “In marine protected areas, we’re managing people’s behavior more than the resources,” says Brumbaugh, who is a CBC researcher as well as the project’s lead. How much a marine reserve’s design has integrated its cultural, economic, and political context can make or break its success. For these reasons, there’s a new trend among marine reserve planners to rely on systematic social research instead of conventional wisdom when establishing reserve boundaries and management.

To help plan The Bahamas’ proposed reserve network, teams of social scientists from the University of Miami, the University of Arizona, and the College of The Bahamas are conducting interviews with citizens across the islands. Some data about how Bahamians use the sea—fishing locations, catch size, revenues—can be quantified for use in computer models. But information assessing Bahamian’s cultural attachment to the ocean and how island life has changed over the decades is anecdotal.

AMNH marine scientist Kate Holmes

Jason Lelchuk for AMNH

Connectivity Work

Unlike a national park on land, which often has natural or humanmade barriers that keep inhabitants from straying, a marine park’s borders are porous. “This leakiness may allow for spillover effects,” says Holmes. “Some species protected within the Exuma park have a greater chance to reproduce. Some of their offspring may mature and move into adjacent unrestricted areas. So human communities can benefit directly from a restricted area.

Most marine species reproduce in multiphase life cycles. After eggs hatch, the fledgling organisms loiter in the water column for a week to several months in their larval phase. Larvae generally have their own locomotion but are also susceptible to the flow of ocean currents. They can sometimes disperse hundreds of kilometers from their hatching site.

“Even species that aren’t super mobile as adults, like the queen conch, have been found to establish high enough densities within the Exuma Cays park to mate easily,” says Brumbaugh. “Their larvae drift outside the park and settle in appropriate habitat to grow into adults.” The research of the Bahamas Biocomplexity Project will build on other research in order to estimate this “reseeding effect.”

“Marine reserves are not going to solve our ocean problem all by themselves,” says Brumbaugh. “You still need other sorts of fisheries management and enforcement. But if we're really interested in large scale restoration of marine areas, we need marine protected areas sprinkled throughout the global oceans. They are incredibly important natural areas that can produce the seeds to resupply surrounding areas. If we let them do it.”

Related Links

What is a Marine Protected Area?http://marineprotectedareas.noaa.gov/aboutmpas/This site from NOAA and the U.S. Department of the Interior clarifies the confusion over the various terms that describe marine reserves and other protected areas.

More About This Resource...

Our innovative Science Bulletins are an online and exhibition program that offers the public a window into the excitement of scientific discovery. This essay was published in August 2005 as part of the Our Oceans, Ourselves Bio Feature.

It begins by stating that just like we have official wilderness areas on land, some people think we need them in the marine realm.

It then takes a look at the Exuma Cays Land and Sea Park, one of the largest no-take marine reserves in the world and the Bahamas Biocomplexity Project.

The essay concludes by explaining the challenge of marine parks and their porous borders.